1. Field of the Invention
This invention relates to release mechanisms for quickly releasing towboats and tugs from one or a string of barges attached to the towboat by means of towing cables. More particularly, the invention relates to a remote control cable release mechanism which improves the conventional pelican hook release devices currently in use. In a typical river barge towing arrangement according to this invention the towboat is connected to a string of barges by means of steel tow cables which may be as large as 11/2 inches in diameter. The tow cables are typically looped through a pelican hook and keeper ring device mounted on the deck of the towboat and around the towboat and barge deck fittings to one or more winches for adjusting the distance between the lead barge or barges and the towboat. The end of each towing cable which is attached to a pelican hook is typically provided with a loop which fits around the neck of the pelican hook near the point of pivot of the pelican hook in the base. The free end of the pelican hook is then pivoted downwardly and forwardly while the cable is slack to facilitate manipulation of a keeper ring, which is slidably attached to the base, over the pelican hook end. The keeper ring thus deployed prevents the pelican hook from pivoting rearwardly on its hinges and releasing the cable loop when tension is placed on the cables by the winch. The barges are then manipulated into alignment with the towboat and are maintained in this orientation while the barges are being towed. Accordingly, in the event of an emergency which requires release of the barges from the towboat, the keeper ring can removed by remote control from the end of the pelican hook, or it can be manually removed by means of a bar or screwdriver during the towing operation.
2. Description of the Prior Art
Conventional pelican hook cable retaining mechanisms have long been used on towboats to releasably secure towing cables to barges and are generally characterized by an elongated pelican hook which is pivotally attached to a pair of hinges welded to a base plate or to the deck of the towboat. The base plate is in turn bolted or otherwise secured to the deck of the towboat and a keeper ring is loosely mounted on a keeper ring stay, which is also welded or otherwise attached to the base or towboat deck adjacent the free end of the pelican hook. Accordingly, the keeper ring is slipped over the end of the pelican hook when the pelican hook is rotated downwardly on the hinges to secure the cable loop of a towing cable between the pelican hook and the base plate or towboat deck and the keeper ring can be removed from the end of the pelican hook during the towing operation by sharply striking it with a sledgehammer to release the cable loop and cable. A disadvantage of manually releasing the keeper ring from the end of the pelican hook in this manner is found in the large amount of stress which is placed on the pelican hook and the keeper ring during towing of a barge or barges. The rearward force on the pelican hook assembly due to the weight of the barge or barges and the force of the towboat pulling the barge string causes the pelican hook to press tightly against the keeper ring. Accordingly, considerable force is required to dislodge the keeper ring from the end of the pelican hook. Accomplishing this act with the aid of a sledgehammer has resulted in injury to the operator, since the force of the pelican hook rapidly pivoting upwardly and rearwardly after the keeper ring is dislodged under towing conditions has, on occasion, knocked the sledgehammer completely out of the hands of the operator. Another disadvantage of the conventional pelican hook is the typically narrow neck or cable-bearing area, which frequently caused flattening and sometimes failure of the cable due to the large stresses applied to the cable.
The most pertinent automatic release mechanism relating to the instant invention which is known to applicant, is the "Underwater Release Mechanism" disclosed in U.S. Pat. No. 3,504,407, dated Apr. 7, 1970, to K. R. Dawson. This device is normally positioned between an anchor and a buoyant member in a water body and includes a housing bifurcated at its lower end and containing a solenoid. The housing is bifurcated in order to receive a pair or interacting lever members and the lower of these members terminates in a hook which is normally positioned to confine a loop member attached to the anchor. When the solenoid is energized, an armature is pulled away from the upper member to release it and this action permits the buoyant force to rotate both of the lever members to release the loop member, allowing the entire device to be carried to the surface by the buoyant member.
One of the problems associated with prior art remote control release mechanisms is the complexity of such devices, a factor which sometimes results in malfunction of the devices due to the relatively large number of parts which must interact in a certain way to achieve the desired result. Furthermore, as heretofore described, conventional manually operated pelican hook and keeper ring cable stay devices are dangerous to trip and require an operator to be in a dangerous position in an emergency. Accordingly, it is an object of this invention to provide a new and improved pelican hook cable release mechanism which is simple in design, easy to operate from a safe and remote location on the boat and includes an improved pivoting pelican hook and positive keeper ring assembly in cooperation with a fluid-activated cylinder to selectively engage and secure a tow cable during barge towing operations and quickly, easily and remotely or manually release the tow cable from the cable release mechanism in the event of an emergency.
Another object of the invention is to provide a new and improved remote control or manual cable release mechanism of the pelican hook and keeper ring design for securing and selectively releasing a tow cable from a tow boat in barge towing operations, which mechanism includes a pelican hook assembly fitted with a hydraulic or air cylinder and a keeper ring, keeper ring spring, ring nut, ring and keeper ring bolt assembly in cooperation with the cylinder piston, with the keeper ring in normally engaged position on the end of the pelican hook during the towing operation and operationally displaced from the end of the pelican hook in remote control mode by activation of the air or hydraulic cylinder and extension of the cylinder piston, or in manual mode, by manual engagement of the ring on the ring nut, when it is desired to release the tow cable and separate the towboat from the barge or barges.
A still further object of the invention is to provide a remote control or manually operated, improved pelican hook and keeper ring cable release mechanism which can be mounted to the deck of a towboat and utilized in cooperation with a standard winch system on the towboat to releasably secure one end of a tow cable and bind a barge string to the towboat, which cable release mechanism is characterized by a pelican hook pivotally mounted on a hinge or hinges attached to a base and a cooperating keeper ring, keeper ring bolt, ring nut, ring and spring cooperating with the piston of a hydraulic or air cylinder also mounted on the base, which cylinder can be activated to extend the cylinder piston against the bias of the spring and remove the keeper ring from contact with the pelican hook in automatic operation, and which ring can be engaged to manually remove the keeper ring from contact with the pelican hook in manual mode, in an emergency situation to release the tow cable from the pelican hook and the towboat.
Yet another object of the invention is to provide an improved automatic or manual cable release mechanism incorporating a pelican hook and a keeper ring assembly and a shaped cable seat on the pelican hook, which mechanism can be mounted to the deck of a towboat for securing the looped end of a tow cable to the pelican hook and removably securing the pelican hook in folded, closed position on the hinges by means of a keeper ring which cooperates by means of a block, a keeper ring bolt, a spring and a ring nut carrying a ring, with the piston of an air cylinder provided with a solenoid valve and appropriate remote controls, in order to facilitate remote activation of the air cylinder and extension of the cylinder piston in remote control operation, or manual engagement with the ring to remove the keeper ring from the pelican hook and release the cable under towing conditions, in the event of an emergency.